Manifesting herself in the backyard of the film’s young Earth-bound heroine, Meg (Storm Reid), Mrs. Which stands at a regal 18 feet — the exact height of Meg’s house. Later on, when the action moves to the alien world of Uriel, she sprouts up to a lofty 35 feet, towering over the lush landscape, as well as over her colleagues Mrs. Who (Mindy Kaling) and Mrs. Whatsit (Reese Witherspoon), not to mention Meg and her kid sidekicks Charles Wallace (Deric McCabe) and Calvin (Levi Miller).

Mrs. Which eventually shrinks to human size for the rest of the sextet’s journey to find Meg’s missing father (Chris Pine). But her introduction effectively establishes her as a force of nature one must look up to, not just in terms of her physical stature, but also thanks to her wisdom and heart. Winfrey’s portrayal has definitely made an impact on audiences, who have taken to Twitter to express their affection for this BFGO — as in Big, Friendly, Giant Oprah.

I’m really glad A Wrinkle in Time exists and I hope it inspires female empowerment among the youth but there’s a scene where Reese Witherspoon turns into a piece of kale and they use her to fly around Oprah who is temporarily giant-sized.

The importance of Winfrey’s role wasn’t stipulated in her contract, of course. Rather, her appearance is DuVernay’s creative extrapolation of a small but memorable detail in L’Engle’s novel. On the page, Mrs. Whatsit has trouble materializing, often taking a little longer to adopt a solid form than her fellow witches. “She’s never quite solid,” Rich McBride, VFX supervisor for A Wrinkle in Time, points out. “She’s still in this slightly transparent form. Materializing is not one of her strong points, as they joke about in the movie. But that first moment with Mrs. Which in the backyard is so important, Ava wanted her to have a real presence — which is a funny thing to say about Oprah Winfrey, because she has a presence of her own anyway!”

Watch an exclusive animatic of the scene where Charles Wallace makes contact with a giant Oprah:

While digital trickery was obviously used to stretch Mrs. Which out to her different heights, McBride confirms that Winfrey — who previously acted for DuVernay in the Oscar-nominated Selma — was physically on set for those scenes, requiring the crew to use old-fashioned movie magic to create the illusion of size. “For the backyard scene, we put her up on a scissor lift, so that the characters were looking up at her and running lines for the scene,” McBride recalls to Yahoo.

“In other cases, we had an eye-line pole to say, ‘Here’s where her eyes will be when you’re addressing her,’ and then she would be off-camera with a mic, so that she could run lines that way.” According to Christopher Batty, a previsualization supervisor at the visualization company Proof Inc., which collaborated with McBride on the big effects sequences, Winfrey was eager to be an active scene partner for her co-stars. “Even when she wasn’t in the frame, she was always on set feeding lines. She’d be standing next to Ava, and they’d give her a mic, and you’d just hear her voice booming through the set. That really helped the other actors.”

Winfrey’s commitment to the film took her all the way to New Zealand, which doubled as Uriel — minus those gossipy, floating flowers and otherworldly vegetation. “When we were on location, the plan was that we would have these various devices to allow the other actors to interact with Oprah,” McBride explains. “We didn’t use the scissor lift there, but we did have the eye-line pole, as well as a TV monitor that was a feed of Oprah saying her lines. We’d put that monitor on a stand high enough that everybody would be looking up at Oprah saying her lines and interacting with her on the TV.”

That location footage was later used as reference and matching material for bluescreen shoots that took place back on the sound stage. “We’d take all of the set-ups that we shot on location to see what elements we were going to need for Mrs. Which, and then lined them with compositing, so you could see where she was going to fit into the shot itself, and shoot her as an element. In some cases, we’d put Oprah up on a 5-foot platform and all the other actors underneath her, based on where they were in the location footage. In both cases, we had principal actors working with each other. Ava was always looking for ways to make sure that everybody could react to each other — especially the kids — so they could feel the emotion of the scene.”

The inside story of Oprah Winfrey’s mind-blowing ‘A Wrinkle in Time’ moments

Because of her height, the early interactions between Mrs. Which and the three kids are mostly emotional rather than physical, with one notable exception. While on Uriel, Mrs. Whatsit transforms into a flying creature that’s part manta ray and part lettuce leaf, and takes Meg, Charles Wallace and Calvin on an aerial tour of the planet. Soaring at 35 feet above the ground, she passes by Mrs. Which’s face, and Charles Wallace reaches out to touch her cheek, a magical moment of contact between a little boy and a giant Oprah.

That effect is all the more magical considering that Winfrey and McCabe were never in the same frame. “We had an accurate pre-viz model of Oprah, and then it was just a case of seeing how close we felt getting a camera to her,” Batty explains. “Once we got framing on her that we liked, we backwards-engineered it to get Derek’s performance. He was standing on top of a bluescreen platform that stood in for Oprah, and if I remember correctly, they had a series of pads for him to physically touch at the appropriate distance away. We also had a finished animatic that we showed him, so he could see what the goal of the shot was; he’s a really smart kid and really savvy, so he knew what the deal was. After that, it was just scaling issues and measurement issues that we had to deal with [digitally] to make the scene work. Even at the last minute, we were trying alternate shots of his performance and Oprah’s performance. Ava always likes to get the best moment she can.”